Well, I agree and disagree with everything here, but rather than comment on all of it, I'll just go up to the original post:

While I can't think of any tube mics that I would recommend under $700, I would go with the K2 if you're locked into that price range and style. I've used one in a couple of studios and was impressed with the performance-to-price ratio.

The K2 also makes the whole preamp decision moot, as it comes with a power supply. I have no experience with CAD gear.

Okay, I do have to side with Noiseboy on the idea that FET mics can certainly outperform tube mics in many situations. Right now I'm pretty hot & heavy with a Charter Oak E700, which I prefer over many of the more expensive tube pieces I have in the locker.

And as far as tube preamps being high end, I had a kid bring a Presonus tube preamp in here a few months ago, and I was astounded at how it managed to make even the best microphones sound like garbage. Just 'cause there's a tube in there doesn't make it a better buy than a similarly-priced solid-state counterpart.

Shandy Lawson
ShandyLawson.com